FROMLIST: power: reset: add reboot mode driver

This driver parse the reboot commands like "reboot loader"
and "reboot recovery" to get a boot mode described in the
device tree , then call the write interfae to store the boot
mode in some persistent storage  like special register or ram,
which can be read by the bootloader after system reboot, then
the bootloader can take different action according to the mode
stored.

This is commonly used on Android based devices, which in order
to reboot the device into fastboot or recovery mode.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>

Conflicts:
drivers/power/reset/Makefile
drivers/power/reset/Kconfig

Bug: 25923642
Patchset: reboot mode PATCH[2/4], reboot fastboot can work.

(am https://patchwork.kernel.org/patch/8016401/)
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Change-Id: Ibcd3b893fa1895503b8f51ac16a4d5068620a604

5 files changed, 186 insertions, 0 deletions

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 17d93a73c51..76a6251b85a 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -166,5 +166,21 @@ config POWER_RESET_RMOBILE
 	help
 	  Reboot support for Renesas R-Mobile and SH-Mobile SoCs.
 
+config REBOOT_MODE
+	tristate
+	depends on OF
+	help
+	 This driver will help to pass the system reboot mode
+	 to bootloader
+
+config SYSCON_REBOOT_MODE
+	bool "Generic SYSCON regmap reboot mode driver"
+	select REBOOT_MODE
+	help
+	 Say y here will enable reboot mode driver. This will
+	 get reboot mode arguments and store it in SYSCON mapped
+	 register, then the bootloader can read it to take different
+	 action according to the mode.
+
 endif
 
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index dbe06c36874..e9765502f31 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -19,3 +19,5 @@ obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o
 obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
 obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o
 obj-$(CONFIG_POWER_RESET_RMOBILE) += rmobile-reset.o
+obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o
+obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o
diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
new file mode 100644
index 00000000000..92b7b4dcef7
--- /dev/null
+++ b/drivers/power/reset/reboot-mode.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/reboot.h>
+#include "reboot-mode.h"
+
+struct mode_info {
+	const char *mode;
+	int magic;
+	struct list_head list;
+};
+
+struct reboot_mode_driver {
+	struct list_head head;
+	int (*write)(int magic);
+	struct notifier_block reboot_notifier;
+};
+
+static int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
+				 const char *cmd)
+{
+	const char *normal = "normal";
+	int magic = 0;
+	struct mode_info *info;
+
+	if (!cmd)
+		cmd = normal;
+
+	list_for_each_entry(info, &reboot->head, list) {
+		if (!strcmp(info->mode, cmd)) {
+			magic = info->magic;
+			break;
+		}
+	}
+
+	return magic;
+}
+
+static int reboot_mode_notify(struct notifier_block *this,
+			      unsigned long mode, void *cmd)
+{
+	struct reboot_mode_driver *reboot;
+	int magic;
+
+	reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
+	magic = get_reboot_mode_magic(reboot, cmd);
+	if (magic)
+		reboot->write(magic);
+
+	return NOTIFY_DONE;
+}
+
+int reboot_mode_register(struct device *dev, int (*write)(int))
+{
+	struct reboot_mode_driver *reboot;
+	struct mode_info *info;
+	struct device_node *child;
+	int ret;
+
+	reboot = devm_kzalloc(dev, sizeof(*reboot), GFP_KERNEL);
+	if (!reboot)
+		return -ENOMEM;
+
+	reboot->write = write;
+	INIT_LIST_HEAD(&reboot->head);
+	for_each_child_of_node(dev->of_node, child) {
+		info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+		if (!info)
+			return -ENOMEM;
+		info->mode = of_get_property(child, "linux,mode", NULL);
+		if (of_property_read_u32(child, "loader,magic", &info->magic)) {
+			dev_err(dev, "reboot mode %s without magic number\n",
+				info->mode);
+			devm_kfree(dev, info);
+			continue;
+		}
+		list_add_tail(&info->list, &reboot->head);
+	}
+	reboot->reboot_notifier.notifier_call = reboot_mode_notify;
+	ret = register_reboot_notifier(&reboot->reboot_notifier);
+	if (ret)
+		dev_err(dev, "can't register reboot notifier\n");
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(reboot_mode_register);
+
+MODULE_AUTHOR("Andy Yan <andy.yan@rock-chips.com");
+MODULE_DESCRIPTION("System reboot mode driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/power/reset/reboot-mode.h b/drivers/power/reset/reboot-mode.h
new file mode 100644
index 00000000000..76646e7111e
--- /dev/null
+++ b/drivers/power/reset/reboot-mode.h
@@ -0,0 +1,6 @@
+#ifndef __REBOOT_MODE_H__
+#define __REBOOT_MODE_H__
+
+extern int reboot_mode_register(struct device *dev, int (*write)(int));
+
+#endif
diff --git a/drivers/power/reset/syscon-reboot-mode.c b/drivers/power/reset/syscon-reboot-mode.c
new file mode 100644
index 00000000000..b9370f3eb74
--- /dev/null
+++ b/drivers/power/reset/syscon-reboot-mode.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include "reboot-mode.h"
+
+static struct regmap *map;
+static u32 offset;
+
+static int syscon_reboot_mode_write(int magic)
+{
+	regmap_write(map, offset, magic);
+
+	return 0;
+}
+
+static int syscon_reboot_mode_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	map = syscon_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	if (of_property_read_u32(pdev->dev.of_node, "offset", &offset))
+		return -EINVAL;
+	ret = reboot_mode_register(&pdev->dev, syscon_reboot_mode_write);
+	if (ret)
+		dev_err(&pdev->dev, "can't register reboot mode\n");
+
+	return ret;
+}
+
+static const struct of_device_id syscon_reboot_mode_of_match[] = {
+	{ .compatible = "syscon-reboot-mode" },
+	{}
+};
+
+static struct platform_driver syscon_reboot_mode_driver = {
+	.probe = syscon_reboot_mode_probe,
+	.driver = {
+		.name = "syscon-reboot-mode",
+		.of_match_table = syscon_reboot_mode_of_match,
+	},
+};
+module_platform_driver(syscon_reboot_mode_driver);
+
+MODULE_AUTHOR("Andy Yan <andy.yan@rock-chips.com");
+MODULE_DESCRIPTION("SYSCON reboot mode driver");
+MODULE_LICENSE("GPL v2");